CNN reported that airlines in multiple countries have suspended the use of Boeing’s new 737 MAX 8 aircraft over concerns about its safety, after an Ethiopian Airlines flight of the same model crashed on March 10, 2019 killing all 157 people on board.

Alongside, Singapore’s Civil Aviation Authority has temporarily suspended the Boeing 737 Max fleet of aircraft from flying into and out of the country.

Flight ET302 to Nairobi had just taken off from the Ethiopian capital of Addis Ababa Sunday when it reported technical problems and asked for permission to turn back. It crashed shortly afterwards.

As the crash investigation got underway, the Civil Aviation Administration of China ordered Monday that all domestic Boeing 737 MAX 8 jets be out of the air by 6 p.m. local time, due to its principle of “zero tolerance for safety hazards.”

China has one of the world’s largest fleets of Boeing 737 MAX 8, operating 97 of the planes, according to Chinese state-run media.

The move was followed by an announcement from Ethiopian Airlines that the carrier had grounded its fleet of Boeing 737 MAX 8 jets as an “extra safety precaution.” Cayman Airways also said on Monday it was grounding both of its “new Boeing 737 MAX 8 aircraft until more information is received.”

Sunday marked the second time in less than six months that a new Boeing aircraft crashed just minutes into a flight. A Lion Air Boeing 737 MAX 8 flight went down over the Java Sea in last October, killing all 189 people on board.

Both crashes are under investigation and there is no evidence of a link between the two, but similarities in the incidents have prompted caution among some airlines.

“Given in both air crashes, the aircrafts were newly delivered Boeing 737 MAX 8, and both accidents occurred during the take-off, they share certain similarities,” the Chinese administration said in a statement. It added that it would contact Boeing and the US Federal Aviation Administration to confirm “flight safety” issues before allowing the planes to fly again.

Mary Schiavo, a CNN aviation analyst and the former Inspector General of the US Transportation Department, called the two incidents “highly suspicious.”

“Here we have a brand-new aircraft that’s gone down twice in a year. That rings alarm bells in the aviation industry, because that just doesn’t happen,” she said.